This invention concerns coupling assemblies for connecting a crane superstructure to a corresponding carrier. More specifically, the invention relates to a releasable mounting clamp for connecting a superstructure and a carrier.
In the past, the most common and most widely used method for attaching a crane superstructure and the turntable on which it rotates to a motorized carrier has been to bolt the turntable directly to the deck of the carrier. Problems have arisen with the transportation and use of large cranes, such as those having large external dimensions and weights which may exceed 100,000 lbs. One such problem relates to the time and effort required to disassemble a crane superstructure from the carrier therefor.
Enactment of highway use laws by various states has placed limits on the size and weight of motor vehicles that may lawfully traverse highways of the respective states. In view of the large dimensions and massive weight associated with a large motorized crane, the crane is often partially disassembled into several subassemblies that are transported independently of one another to a job site. Typically, a crane is disassembled into a number of subassemblies such as a boom assembly, an upper assembly comprising the crane superstructure and a lower assembly comprising the carrier.
Where the turntable of the superstructure is mounted on the deck of a carrier in accordance with the widely used method, as many as 50 separate bolts have been required. Needless to say, the assembly and disassembly of the carrier and superstructure subassemblies alone necessitates a substantial expenditure of time on every occasion when either assembly or disassembly must be effected. Moreover, since the crane is inoperative during assembly, the loss of productive time increases expenses of the owner above the expense naturally concomitant with having workmen effect the crane assembly by installing 50 or more bolts.
One approach to reducing the time and expense associated with crane assembly and disassembly operation has involved the use of a tang and wedge system in which a plurality of downwardly extending tangs on the turntable of a crane must be aligned with slots of a carrier and locked in place by multiple part adjustable wedges. Although some time savings are claimed for such systems, it is believed that they in turn present practical disadvantages, and there has remained a need for truly practical apparatus which can be actuated rapidly to disconnect, and connect, the superstructure and carrier without substantial expenditures of time and effort.